Is ghusl and purification of clothes required if semen is discharged during sleep?

Whoever experiences a wet dream and finds wetness on their garment must perform ghusl (ritual bath). However, whoever experiences a wet dream but does not find semen is not required to perform ghusl. As for garments, it is prescribed to wash the wet trace of semen from them. If it is dry, it suffices to rub it off with the hand, as semen is considered pure according to the preponderant opinion.